As a next-generation energy source, various fuel battery devices generating power using hydrogen-containing gas and oxygen-containing gas have been proposed.
In general, such fuel battery devices are configured to house a fuel battery cell device, in which a plurality of fuel battery cells are combined, in a housing and generate power by supplying fuel gas (hydrogen-containing gas) to a fuel electrode layer of each fuel battery cell and supplying air (oxygen-containing gas) to an oxygen electrode layer. The plurality of fuel battery cells are electrically connected to each other in series with a felt-like or plate-like collector member.
Such a collector member is generally formed of a Cr-containing alloy having high workability and heat resistance.
However, when the collector member is formed of the Cr-containing alloy and is exposed to a high temperature atmosphere in the air or the like, diffusion of Cr (hereinafter, may also be referred to as “Cr diffusion”) from the alloy to the fuel battery cells may occur at the time of operating the fuel battery cell device. Thus, in addition to a decrease in the performance of a fuel battery cell, there is a problem in that the heat resistance of the alloy decreases with a decrease in the amount of Cr contained in the alloy.
Therefore, in order to reduce such Cr diffusion, there has been proposed a composite body in which a second composite oxide layer having a spinel type crystal structure, a first largest content, a second largest content, and a third largest content of the second composite oxide layer being Zn, Cr, and Mn, a first composite oxide layer having a spinel type crystal structure, a first largest content and a second largest content of the first composite oxide layer being Zn and Al, and a zinc oxide layer or a third composite oxide layer having a spinel type crystal structure, a first largest content and a second largest content among constituent elements excluding oxygen of the third composite oxide layer being Zn and Mn are sequentially stacked on a surface of a substrate containing Cr (refer to PTL 1).
In PTL 1, the first composite oxide layer having a spinel type crystal structure, a first largest content and a second largest content of the first composite oxide layer being Zn and Al, may be directly disposed on the surface of the substrate containing Cr, and the third composite oxide layer may be disposed on the first composite oxide layer.